Booking a Dummy Return Flight to Japan

You don't want to book something that's on a waitlist for your departing flight you need that one to be available now. Your only competition really is people in Japan looking to make a trip to the US and that seems to be a way smaller number than people in the US trying to make atrip to Japan. Once you've secured your outbound with the dummy inbound flight you'll just need to set a reminder to call back in a couple weeks or a week or it just depends on when you're planning on returning from Japan.